Palmitoyl Pentapeptide-4 (Matrixyl)

What it is, and what it is called

Palmitoyl pentapeptide-4 is the ingredient-label (INCI) name for a five-amino-acid chain, Lys-Thr-Thr-Lys-Ser (KTTKS), joined to palmitic acid, a fatty acid. [1] The sequence is a fragment of procollagen I, and the fatty acid was added to help the peptide pass through the skin's outer layer. [1] Researchers abbreviate it Pal-KTTKS. [2]

The same page of names has traps:

• Pentapeptide-4, palmitoyl pentapeptide-4 and myristoyl pentapeptide-4 are three separate ingredient entries: the bare peptide, the palmitic acid version and a myristic acid version. [1]
• "Pentapeptide" is not one molecule. A 2011 review said KTTKS had become wrongly equated with the word "pentapeptide", although many other five-amino-acid peptides exist. [3]
• Matrixyl is a trade name. One academic paper uses "Matrixyl" for Pal-KTTKS. [4] Matrixyl 3000 is a different blend containing palmitoyl tripeptide-1 and palmitoyl tetrapeptide-7. [5] See that page.

A product label that says "Matrixyl" or "pentapeptide" therefore does not by itself tell you which molecule is inside. This page uses promising but limited, preclinical (cells/animals only), insufficient evidence and marketing claim as evidence labels.

Proposed mechanism

In cultured skin cells (fibroblasts), KTTKS stimulated production of collagen types I and III and fibronectin, which a review called a sound laboratory basis for the idea. [3][1] That is preclinical (cells/animals only) evidence. Whether the same happens in living skin after a cream is applied depends on how much reaches the target layer, which the next section covers.

Human studies

• 12-week split-face trial, 93 women aged 35 to 55 (promising but limited). A moisturizer with 3 ppm Pal-KTTKS was compared with the same moisturizer without it. The peptide side showed significant improvement in wrinkles and fine lines by image analysis and expert grading, and the peptide was well tolerated. [2] The authors were from Procter & Gamble. [2]
• Earlier reports, summarized in a 2026 review. A 4-month study compared 5 ppm Pal-KTTKS with vehicle in 30 and 30 people, and a 16-person study used 3 ppm. [1] I read only the review's summary, not those papers, and the review's authors also work for Procter & Gamble. [1]
• 2023 trial in 21 Indonesian women (insufficient evidence). Three groups used an acetylhexapeptide-3 cream, a palmitoyl pentapeptide-4 cream, or placebo for eight weeks. The pentapeptide cream looked better than the others, but the authors called it an initial study needing more samples and a longer follow-up. [6]
• Animal wound-healing work. An animal study of "Matrixyl" cream and patches reported faster wound healing. [7] It is not evidence of wrinkle improvement in people.

A 2011 review found few clinical studies and surprisingly little skin-penetration data. [3] I did not find a newer human penetration study on this exact ingredient in my searches.

How to read a label or a claim

A study of a moisturizer containing 3 ppm of the peptide tests that whole moisturizer, including the cream base, not only the peptide. [2] Read ingredient evidence vs finished-product evidence and cosmetic peptide outcomes before comparing products.